The Occupy Wall Street protests that began as a nebulous mix of social and economic grievances are becoming more politically organized — with help from some of the country’s largest labor unions.

Labor groups are mobilizing to provide office space, meeting rooms, photocopying services, legal help, food and other necessities to the protesters. The support is lending some institutional heft to a movement that has prided itself on its freewheeling, non-institutional character.

And in return, Occupy activists are pitching in to help unions ratchet up action against several New York firms involved in labor disputes with workers.

In one case, Occupy activists have helped union workers disrupt the rarified environs of Sotheby’s art auction house, which is engaged in a contract dispute with about 40 of its art handlers.

A joint demonstration of Occupy activists and telephone workers is planned for Friday to target Verizon, and Occupy organizers say more unions are reaching out to a newly formed labor relations committee to ask for help in planning future actions.

The coordination represents a new chapter for the anti-Wall Street activists, who have expressed anger at establishment forces in both major political parties and eschewed the traditional grass-roots organizing tactics long deployed by labor unions.

It also suggests an evolution for organized labor, which retains close ties to President Obama and the Democratic Party but sees the Occupy protests as a galvanizing moment. Some union officials concede that their efforts to highlight income inequality and other economic concerns have fallen short, scoring few victories with a White House that many on the left see as too close with Wall Street.

“Our members have been trying to have this discussion about Wall Street and the economy for a long time,” AFL-CIO President Richard Trumka said in an interview. “This movement is providing us the vehicle.”

Leaders in both camps acknowledge that joining forces does not necessarily make for an easy marriage. Some Occupy activists consider it a chance to push the increasingly weak union movement into a more aggressive posture.

“We’re hoping this will inspire them to take on more militant tactics,” said Jackie DiSalvo, an Occupy Wall Street organizer who has been coordinating with labor. “The fact that they’re willing to support more militant tactics might mean that they’re willing to start doing more.”

In the case of Sotheby’s, Occupy activists have attended auctions in recent days, masquerading as clients. They have stood up abruptly to disrupt proceedings with loud accusations that the company reaps millions in profits and rewards executives with handsome raises while refusing its unionized workers’ requests for better pay and benefits.

Occupy activists also showed up at a Manhattan restaurant owned by a prominent Sotheby’s board member, clinking on beer glasses to quiet the crowd and then denouncing the company as a “union buster.” A video of the scene was posted on YouTube.

Jason Ide, president of Teamsters Local 814, which represents the art handlers, said the Occupy tactics surprised and inspired him and his members — so much so that the workers have become regulars at Zuccotti Park, the Wall Street plaza that protesters have occupied for weeks.

“Now is this rare opportunity for labor unions, and especially the union leadership, to take some pointers,” Ide said, adding that unions should consider the civil-disobedience approach taken by Occupy demonstrations.

“The whole Zuccotti Park thing is quasi-legal,” he said.“Unions, we have to obey the law. But sometimes it’s time to think outside the box.”

A Sotheby’s spokeswoman, Diana Phillips, said that the tactics are counterproductive and that company officials feel that they have been negotiating in good faith.

“There have been a few attempts to interrupt our sales, but they have not been successful,” she said. “Sotheby’s has offered a fair and reasonable contract to our union colleagues, and we want to bargain at the table to reach an agreement that will allow them to come back to work.”

The union involvement in Occupy Wall Street reached an apex last week, when the firm that owns Zuccotti Park asked New York Mayor Michael R. Bloomberg (I) for help clearing the area so that it could be cleaned. The park owner eventually backed down.

Several labor groups, including Service Employees International Union Local 1199, dispatched thousands of members to the park by 6 a.m. last Friday to help protesters stand their ground. Meanwhile, Vincent Alvarez, president of the AFL-CIO’s Central Labor Council in the city, spoke with City Hall aides to dissuade Bloomberg from removing the activists, union officials said.

Union members and organizers have also pitched in for demonstrations in Boston, Sacramento, St. Louis and Los Angeles. Some union members have been camping out in Los Angeles, and in every location, Trumka said, union halls are being opened to protesters for meetings or respite.

In New York, protesters are storing gear at a teachers union hall. Some of the committees that have been formed to govern the group are meeting at a union office for City University of New York faculty and staff. SEIU members, many of them health-care workers, are pitching in to provide medical support, and other union members are donating rain ponchos, T-shirts, food and water.

SEIU plans to print an edition of the movement’s makeshift newspaper, the Occupied Wall Street Journal.

“I have been shocked at how much support has come from labor,” said DiSalvo, 68, a retired English professor who helped form the Occupy Wall Street labor committee. “I think they feel this is giving their ranks some juice.”

Leaders in both camps say the relationship is sensitive. Occupy activists have made it clear that they would reject any efforts by union officials to draw the new movement into the get-out-the-vote efforts that labor wages in election campaigns.

Unions mobilized in 2008 to help elect Obama, and, despite frustrations with the administration, unions are expected to follow suit again next year.

George Gresham, president of SEIU 1199, the union’s biggest local, said he hopes the coordination with Occupy Wall Street will eventually push the activists toward a focus on the 2012 election.

He said it was “the reality of the world we’re living in now” that “there is going to be an election in a year and a half, and someone is going to come out of that election to lead this country.”

Gerald McEntee, president of the American Federation of State, County and Municipal Employees, one of the unions coordinating with Occupy, said AFSCME planned to once again spend as much as $100 million next year to help Obama and other Democrats. He also said he expected the activists to turn their energy toward the campaign. “What’s the alternative?” he asked.

DiSalvo, of the Occupy group, said the unions should not count on the activists’ help in waging political campaigns. “There’s no way that people are going to be led by the unions into becoming focused on elections,” she said. The activists “really feel that that has been unsuccessful.”

Trumka said the unions will not try to guide the protesters down that path. “This is an organized movement, and we’re not attempting in any way to try to harness it,” he said. “We’re just riding along with it.”

Still, Trumka’s recent schedule illustrates the challenge of trying to balance the establishment and the anti-establishment.

Two weeks ago, he was charming Occupy activists with a personal visit and a delivery of hundreds of fresh bagels. But this week, he sat down for a private meeting with the ultimate insider: Treasury Secretary Timothy F. Geithner.